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N. PETERS, NIQTOIJTHOGRAPMEL WISHINGYDN. D-CA outer ends of this lever L are pivoted rods R and R, the lower ends of which are pivoted to the levers L l When the steam :has been raised to the desired pressure the v to bring it in contact with the end of the valve-stem a,

` 's'uit the circumstances of the case. This being done, the instrument m fr. a strat firs-r.

D. M. GREENE, or WASHINGTON, nISrRIe'r or COLUMBIA, ASSIGNoR To MARIA N. GREENE, or SAME PLAGE.

Lata-s Patat No. 70,080, amant-aa.- 22, Iscr.

IMPROVEMENT IN STEAM-GENERATOR INDICATORS.

To ALLfWHoM 1T MAY eoNoERN:

Be it known that I, D.' M. GREENE, of Washington, in the county of' Washington, and District'of Columbia, have invented certain new and useful Improvements in Indicators for Steam-Boilers; and I do hereby. declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, l'aking part of this specification, and to the letters of' reference marked thereon; like letters indicating.

like parts wherever they occur. y

To enable others skilled in the art to construct and use my invention, I will proceed to describe it.

My invention consists of en apparatusso lconstructed that when attached to a steam-boiler the temperature vof the steam shall cause an alarm to sound whenever the pressure exceeds a certain degree, and which shall also `sound a similar alarm whenever the pressure falls below a certain other specified degree, and which mayalso be made to-serve -as a low-water indicator for the boiler. i

Figure 1 is a front elevation shown partially in section,

Figure 2 is a side elevation, and

Figure 3 a top plan view.

Theobject of my invention is to produce an instrument that can be attached to the exterior of a steam,-

boiler, and sound an alarm Whenever the pressure of the steam rises above the required degree, or falls below a certain other specified degree, and thus to keep the pressure at all times within certain specified limitsfthe i instrument being made adjustable to 'adapt it to varying degrees of pressure, as maybe Vrequired in dili'erent cases, or which, instead of indicating the high and low degrees of pressure, may be used to indicate 'thehigh pressure, and at the same time act as a'low-water indicator. It isa wellsestablished fact that 'the pressure of steam increases with an increase of its temperature, and it is upon the application of this principio that my instrument depends for its operation.

I provide a tube, P, which I connect with theV boiler by a short tube, H,- having aflange, A B, for bol-'ting it to the boiler, as represented in igs. 2 and 3. The lower end of the tube P is closed, and terminates in n; 'solid portion, D, which is divided into two lateral arms or brackets, as shown in fig. 1.- Freniv opposite sides -of the tube'P, near its bottom, project short tubes leading to valvc-chambers V and V, from which risc tubes P and P, [upon each'of which is mounted a steam-whistle, W and W', as represented in g. 1. From the side of the steamstube P a stud, I2, projects, to which is secured a vertical rod, l, the upper Yend of which isp'ivoted to a lever, L, said lever being pivoted at its centre to the topof the steam-tube P, as shown clearly in iig.` 1. Lo the and (one or when the levers are moved, as

L, said levers being pivoted to the extremities ofthe arms or brackets D, and having their inner ends both) provided with set-screws, arranged to press onthe valve-stems a and a hereinafterdeseribed. I

A The instrument being thus constructed and applied to the boiler, the operation is as follows: The steam as it is raised in the boiler enters the pipe or tube P, which is thereby heated in proportion to the temperature of the steam. And to keep the tube at this corresponding temperature, and prevent itfrom becoming cooled by a condensation ofthe steamin its upper part, a small orifice, t, is provided near its upper end, as shown in fig. 1, from which a very'small jct'of steam is allowed to escape, so as to keep up a current of steam in the tube P. rod vR is adjusted by means ofthe nuts es', so as to draw the leverIL up in contact with the projectingend ofthe va1ve-stem a', this being the pressure above'whieh it is intended the steam shall not be allowed to go to any great extent. The steam is then allowed to fall to the lowest point at which it is intended te have it go, and the set-screw s inthe end of lever L is so adjusted as the degrees of pressure, both high and low, of course,

being optional, as is also the range between these limits, either or beth being changed, as may be desired, to# ay be considered adjusted, ready for' ure, it will be expanded, thereby, of ncrease of temperature and pressurer is not expanded like the tube P, it follows that operation. New, as'steam chte/rs the tube P and increases its temperat course, increasing itslengthf; 'and as this expansion continues with thci and as the rod R, being insulated and unaiiected by the steam,

`the` right-hand arm of lever L will bc elevated bythe expansion of the-tube l), amd asit moves will also elevate the lever L', by means of the connecting-rod lt', and thereby vopen the valvev, thus permitting the steam to flow through pipe P', and atonce sound an alarmby blowing the whistle W', as soon as the steam has risenabove the pressure at which the instrument had been previously adjusted, as described. On the other hand, as the pressure and temperature decrease the tube P contracts, thereby elevating the left-hand arm oflevr L, and by means of the connectingfrod R'l raisesthelever L", thcreloy opening the valve in the valve-chamber V, thus permitting the steam to flow through pipe vP", arid's'ouliding an alarm by blowing the whistle W. In this way thc instrument operates as a differential pressure alarm oi' indicator, and automatically notities the attendant whenever the pressure exceeds or falls below the required degree. i A i Y AS, however, the falling ofthe pressure below the designated point is not attended with any special danger,

and is not, therefore, of so much importance, this feature may be dispensed with, an'd this part of the instrument` be convertedlinto a low-water indicator by providing it with a separate steam-tube, P, androdR, and-connecting the levers to them, so aste operate independentiofthe highsprcssu're alarm. In such c'as'e apipe, P3, will enter the vboilerafnd have its mouth immersed` in the Water, as represented in fig. Whenever'the water'inthc boiler is solowered as to uncover the mouth ofthe pipe P3, the'steam vwill pass through it up into the tube l), and by heating and expanding itwill open the valve in the chamber V, andsound an alarm by v-bloi'vingthe' whistleW,

as previously described, and thus the instrument becomes a. high steam-pressure indicator, andal'so-'a lowdvater indicator,V A'It is obvious thatin such case the two part: will operate independently, and may be made and applied separately; but, for the purpose ofvmaking it more symmetrical and convenient of eonstruction'and application,

I prefer to make it in the manner described.

It may bedes'irable to form the working-Joints ofthe levers on the knifefedge plan, as is done in scalesand 4similar mchines, to permit of their working with greater freedom and accuracy.y This'eonstr'uction of an indieater adds greatly to the safetyof steam-boilers, by indicating danger from excess of steampressure, and is important as an indieatoref an insuficiency of heat and steam.

Having thus 'described my invention, what I claim is Y 1. The combination of steam -pipe P, stationary rod R, levers L, L', and L", connected bythe rods It' and E", arranged substantially as described. i i i v2. The steam pipe P, stationary rod R, levers Land' L', valve v, and the whistlevW', arranged substantially as set forth. v N

yD. MAGREE E.

Witnesses: f y

W. C. DODGE, OTTO .LEIssmNm 

